贾第虫病

　　贾第虫滋养体牢固地吸附于十二指肠和近端空肠的粘膜并营二分裂繁殖.释出的虫体很快转化为对外界环境有抵抗力的包囊,包囊随粪排出后经粪-口途径传播.水源性传染是贾第虫病的主要传染源。此外也可经人-人间接触直接传染,这种传染在精神病院,日托中心或性伙伴间尤为常见。通过土壤过滤的水可清除贾第虫包囊,但在浅表水中的包囊仍是活的,并能抵抗常规浓度的氯化处理。除人以外,野生动物可成为其保虫宿主。因此山中的溪水和虽经氯化处理但未经严格过滤的城市供水系统是水源性流行的根源。

　　贾第虫感是世界性分布的,在儿童和卫生状况差的地区尤为常见.在美国,贾第虫病是最常见的肠道感染之一。经常去多国旅行的人,乱交的男性同性恋者,胃被切除者,慢性胰腺炎患者及低丙球蛋白血症患者的感染率尤为较高。

　　What complications can Giardiasis easily lead to?

　　What are the typical symptoms of Giardiasis?

　　Most Giardiasis patients are asymptomatic, but they can excrete infectious cysts, so they must be treated. The symptoms of acute Giardiasis usually appear 1 to 3 weeks after infection. The symptoms are generally mild, including watery, malodorous diarrhea, abdominal spastic pain, and distension, gastrointestinal bloating and belching, intermittent nausea and upper abdominal pain, and may also appear low fever, chills, discomfort, and headache. Severe cases may experience significant weight loss due to poor absorption of fat and sugar. There is usually no blood or mucus in the stool.

　　How should Giardiasis be prevented?

　　1. Strengthen the management of water source hygiene, pay attention to dietary hygiene, thoroughly treat patients and asymptomatic cyst carriers, eliminate the vectors such as cockroaches and flies, do a good job in the harmless treatment of feces, and maintain normal immune function.

　　1. Pathogen examination

　　Trophozoites can be found in fresh diarrhea stools, while cysts are mostly found in pasty stools and formed stools. Trophozoites can be found directly on the physiological saline smear of feces; after staining with iodine solution, cysts can be easily identified. Concentration methods such as zinc sulfate floatation can improve the detection rate of cysts. Fecal examination should be sent three times and checked three times, which can increase the positive rate to 97%. Duodenal drainage, small intestinal mucus, or biopsy tissue can all detect the parasites.

　　2. Immunological tests

　　It can be divided into two categories: detection of antibodies in serum and fecal antigens.

　　(1) Detection of antibodies: Since the pure culture of Giardia lamblia has been successfully established, due to the possibility of high-purity antigen preparation, the sensitivity and specificity of immunodiagnosis have been greatly improved. China has established two strains of Giardia lamblia culture, providing conditions for the development of immunodiagnosis in China. Enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent antibody test (IFA) are used to examine patient serum antibodies. The former can reach 75% to 81% positive, and the latter can reach 66.6% to 90% positive.

　　(2) Antigen detection: Enzyme-linked immunosorbent assay (double sandwich method), dot enzyme-linked immunosorbent assay (Dot-ELISA), immunoelectrophoresis (CIE), and other methods can be used to detect antigens in fecal dilution. The positive rate of double sandwich ELISA can reach 92%, Dot-ELISA can also reach 91.7%, and CIE can reach 94%. The detection of fecal antigens can not only be used for diagnosis but also to evaluate the efficacy.

　　3. Molecular biological diagnosis

　　In recent years, polymerase chain reaction (PCR) has been used to detect the ribosomal RNA (rRNA) gene products of the blue-green Giardia flagellum, which can detect amplification copies equivalent to the amount of DNA in a trophozoite genome, and radioactive-labeled chromosome DNA probes can also be used to detect trophozoites and cysts. The molecular biological method has high specificity and sensitivity, and thus has a broad application prospect.

　　Abdominal ultrasound to understand the liver and gallbladder conditions, and X-ray chest film and electrocardiogram should also be performed.

　　It is advisable to eat light food and have a reasonable diet. There are no special contraindications, and a reasonable diet should be maintained according to daily conditions. It is advisable to eat acidic foods; it is advisable to eat foods high in fiber; it is advisable to eat foods rich in probiotics.

　　Oral metronidazole (adults 250mg taken 3 times a day for 5 consecutive days; children 15mg/kg per day taken 3 times a day for 5 consecutive days) is effective, but has not been approved for the treatment of Giardiasis in the United States. The side effects include nausea, headache, and less common symptoms such as dark urine, paresthesia, and dizziness. Oral artemisinin (adults 100mg taken 3 times a day for 5 consecutive days; children 2mg/kg taken 3 times a day for 5 consecutive days, with a maximum daily dose not exceeding 300mg) can achieve high efficacy, but can cause gastrointestinal disturbance, dizziness, and headache, and occasionally may cause exfoliative dermatitis and toxic psychosis, so it is no longer used in the United States. Oral furazolidone (adults 100mg taken 4 times a day for 7 to 10 days; children 6mg/kg per day taken 4 times a day for 7 to 10 days, although the efficacy is not as good as metronidazole and artemisinin, it can be made into a suspension for children.